Airbnb is engaged in a spat with the City of New York's Office of the Comptroller over a report issued in May of 2018 that found Airbnb was one of the reasons rents in New York City are rising.(Photo: John MacDougal, AFP/Getty Images)

SAN FRANCISCO — Expert or flawed? Airbnb and its largest market are engaged in an increasingly acrimonious fight over a report produced last week by New York City's comptroller, which says it found the service's short-term rentals contribute to rising housing costs.

It's just the latest round in a dispute between cities and the San Francisco-based housing rental company over the increasing number of homes and apartments that are offered on the site, which some cities say takes rental units out of the market for long-term residents and contributes to rising housing costs.

New York's report on the impact of Airbnb on New York City rents, issued on Friday, found that for each 1% of residential units in a neighborhood listed on Airbnb, rental rates went up by 1.58%. The number was much higher in neighborhoods popular with tourists. Overall, it found that between 2009 and 2016, about 9.2% of citywide rent increases could be attributed to Airbnb.

"New York City renters had to pay an additional $616 million in 2016 due to price pressures created by AirBNB," the comptroller's report said.

It used data gathered from AirDNA, an independent company that offers analytics tools to real estate investors, Airbnb hosts, and vacation rental management companies by scraping data from the Airbnb website. The report found 36,000 New York City units listed on the site last year.

On Saturday AirDNA issued a statement calling the report "deeply flawed" because, it said, many listings on Airbnb aren't active and so don't have an effect on what housing is available. It also said that the city shouldn't have lumped the rental of a room in a house or apartment in the same category as an entire house or apartment rented out.

.@Airbnb cannot have it both ways. It cannot hide its raw data behind a wall of attorneys, then cry foul when others use what data is available to measure “the Airbnb effect” on the local rental market.

The comptroller's office said that whether a listing was active or not was irrelevant because it was measuring the average effect of Airbnb listings. New York and other cities have also noted that Airbnb makes it difficult for them to accurately gauge the effects of the service because it does not readily make data available to cities.

"Airbnb does not make this level of detail publicly available. So if Airbnb wants to make the argument that this is a relevant factor, they should hand over the data so that their claims can be independently reviewed," the response read.

Airbnb responded in turn on Monday, issuing an open letter to the comptroller. "Responsibility in a democracy includes ensuring that government officials provide objective facts and do not abuse their powers to misuse information, especially in an effort to advance their own political career," it said.

During a call with reporters Monday morning, Airbnb's head of global policy Chris Lehane called for a retraction of the report, which he said was inaccurate, "a report that was improperly obtained, a report that’s wrong on the fact, a report that’s wrong on the methodology and a report that’s wrong on the conclusion.”

Lahane also made oblique reference to the possibility that the hotel industry might have been partly behind the report. Airbnb and the hotel industry have been engaged in an ongoing and often proxy fight over its growth, which has cut into hotel profits and pulled guests away from traditional hotels and into Airbnb and short-term rental situations.

Asked if he suspected that the hotel industry had somehow supplied the comptrollers office with the data used in the report, Lehane said, "I would say if the hotel key fits in the door, turn it.”

Hotel Association of New York did not immediately respond to a request for comment.

New York state is currently discussing several laws that would regulate short-term rental companies in the state. Airbnb has insisted that what’s needed is a legal framework that allows people to make extra money by renting out space in their homes but that weeds out people who game the system by keeping apartments off the rental market.

“Most of the big cities in the country have figured it out,” Lehane said.

In 2016, after a nearly two-year fight, Airbnb agreed to San Francisco rules that limited hosts to no more than 90 days of rentals for entire homes or apartments. Last month a Los Angeles city council committee voted to regulate short-term rentals, though the law still must be approved by the full council.